handle the case when the script silently fails producing an empty data file

Author: motus

mlos_bench/mlos_bench/environments/local/local_env.py

@@ -206,7 +206,10 @@ def run(self) -> tuple[Status, datetime, dict[str, TunableValue] | None]:
         )
 
         _LOG.debug("Read data:\n%s", data)
-        if list(data.columns) == ["metric", "value"]:
+        if len(data) == 0:
+            _LOG.warning("Empty metrics file - fail the run")
+            return (Status.FAILED, timestamp, None)
+        elif list(data.columns) == ["metric", "value"]:
             _LOG.info(
                 "Local results have (metric,value) header and %d rows: assume long format",
                 len(data),

mlos_bench/mlos_bench/optimizers/mlos_core_optimizer.py

@@ -280,7 +280,10 @@ def bulk_register(
         df_configs = self._to_df(configs)  # Impute missing values, if necessary
 
         df_scores = self._adjust_signs_df(
-            pd.DataFrame([{} if score is None else score for score in scores])
+            pd.DataFrame(
+                [{} if score is None else score for score in scores],
+                columns=list(self._opt_targets),
+            )
         )
 
         if status is not None: